UPDATE 2-Ex-SVB CEO says was unaware of bank's problems when he sold stock

(Adds context in paragraph 2,3 and 5, Becker quote in paragraph 6, background in paragraph 11)

By Hannah Lang and Tatiana Bautzer

WASHINGTON/NEW YORK, May 16 (Reuters) -

The former chief executive of Silicon Valley Bank was unaware the U.S. lender was in trouble when he sold stock weeks before it failed, he told senators in his first public comments defending his conduct after the lender's shock collapse.

California banking regulators shut down Silicon Valley Bank on March 10 after depositors withdrew $42 billion in 24 hours, sparking a rout in bank shares globally and investor fears of contagion spreading to other banks.

Two other U.S. regional lenders have since failed, marking the biggest turmoil to grip banks since the 2008 financial crisis.

In his comments, former SVB CEO Greg Becker painted a picture of an unprecedented, unforeseeable crisis that unfolded at lightning speed despite the bank taking risk management seriously and having liquidity of around $80 billion at the end of last year.

"I believe it was a series of unprecedented events that all came together in the fastest bank run in history," Becker told the Senate Banking Committee.

Tuesday's hearing for the first time offered lawmakers the opportunity to grill Becker, who has been criticized for failing to address risk-management issues that had been flagged by regulators. Some lawmakers have also rebuked Becker for dishing out bonuses and have questioned whether he and other executives profited from stock sales ahead of the bank's collapse.

Becker sold SVB stock in the first quarter with the largest sales on Feb 27, public records show.

"I was the CEO of Silicon Valley Bank, I take responsibility for what ultimately happened," Becker said.

Lawmakers on both sides of the partisan divide, though, were unimpressed.

"Why did you ignore admonitions from regulators?" Senator Sherrod Brown, a Democrat, said in his opening statement.

"There is a simple answer, the same answer we find for most big bank failures -- because the executives were getting rich."

Responding to criticism about the bank lacking a chief risk officer in the months leading up to its collapse, Becker said he had been told by regulators to look for a more experienced executive for the position. He also said he would cooperate with regulators as they reviewed SVB's executive compensation.

SVB's downfall was triggered by holdings of long-term Treasuries losing value as interest rates rose quickly - a risk the bank had not hedged. The bank tried to cover the loss by raising capital, but in announcing the transaction helped fuel a bank run.

"Mr. Becker you made a really stupid bet that went bad, didn't you," said Senator John Kennedy, a Republican. "And the taxpayers of America had to pick up the tab for your stupidity."

(Reporting by Hannah Lang in Washington and and Tatiana Bautzer in New York, additional reporting by Saeed Azhar; Editing by Lananh Nguyen, Michelle Price and Deepa Babington)